Real estate investment decisions in Europe are lacking hard facts on the financial viability of a sustainable asset management. In the United States, Great Britain and Australia, recent research had observed financial premiums for certified green buildings. But no corresponding research had yet been performed into commercial real estate in Europe. Therefore this empirical study aimed at the search for a rational link between sustainable management and financial performance of retail and office properties in Europe. The study was focused on existing buildings and their performance at asset level. The first step profiled the attribution of the sustainability performance for properties from standing real estate portfolios. The second step defined an analytical approach to the pricing of sustainability externalities in European property markets. And the third step measured the contribution of the sustainability management to sustainable investment performance, the so-called 'green alpha' impact. The data was provided by the pan-European research platform Sustainable Investment in Real Estate s-i-r-e, an independent network of institutional investment and management companies in real estate, headed by the EURO Institute of Real Estate Management. The performance indicators were adopted from the Global Reporting Initiative GRI and its Construction and Real Estate Sector Supplement CRESS. The statistical analysis followed conventional practice of single linear and multiple logistic regression models. As a result of this study the first sustainability report according to the new industry standard GRI CRESS was established on the GRI application levels C and B. The 'green alpha' methodology for the pricing of externalities was robustly defined and tested with a large real world portfolio, taking into account econonic fundamentals, property characteristics, and financial, environmental and social performance. First market evidence for 'green alphas' of sustainable asset management was successfully identified in selected office and retail markets, although the need for more consistent data became clearly apparent. The project was directed by Danube University Krems, Department of Building and Environment, in co-direction with Kingston University London, School of Planning and Surveying. It was awarded grants by the Royal Institution of Chartered Surveyors RICS Education Trust and the Austrian Chamber of Commerce, Federation of Real Estate Professionals.